apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: require-app-label
  annotations:
    policies.kyverno.io/title: Require App Label
    policies.kyverno.io/category: Zero Trust
    policies.kyverno.io/severity: low
spec:
  validationFailureAction: Audit
  background: true
  rules:
    - name: require-app-label
      match:
        any:
          - resources:
              kinds:
                - Deployment
                - StatefulSet
                - DaemonSet
      exclude:
        any:
          - resources:
              namespaces:
                - kube-system
                - kube-node-lease
                - kyverno
                - rook-ceph
                - default
                - crowdsec
                - gitlab
                - scylla-manager
                - scylla-operator
                - cert-manager
      validate:
        message: "The label 'app' or 'app.kubernetes.io/name' is required."
        anyPattern:
          - metadata:
              labels:
                app: "?*"
          - metadata:
              labels:
                app.kubernetes.io/name: "?*"